Double Helicity Asymmetry in Inclusive Midrapidity$\pi^0$ Production for Polarized p+p Collisions at $\sqrt s$=200 GeV

Abstract : We present a measurement of the double longitudinal spin asymmetry in inclusive pi^0 production in polarized proton-proton collisions at sqrt(s)=200 GeV. The data were taken at the Relativistic Heavy Ion Collider with average beam polarizations of 26%. The measurements are the first of a program to study the longitudinal spin structure of the proton, using strongly interacting probes, at collider energies. The asymmetry is presented for transverse momenta 1-5 GeV/c at mid-rapidity, where next-to-leading order perturbative quantum chromodynamic (NLO pQCD) calculations describe the unpolarized cross section well. The observed asymmetry is small and is compared with a NLO pQCD calculation with a range of polarized gluon distributions.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00023732
Contributor : Suzanne Robert Connect in order to contact the contributor
Submitted on : Wednesday, February 9, 2005 - 11:32:18 AM
Last modification on : Tuesday, April 20, 2021 - 12:00:07 PM

Citation

S.S. Adler, S. Afanasiev, C. Aidala, N. N. Ajitanand, Y. Akiba, et al.. Double Helicity Asymmetry in Inclusive Midrapidity$\pi^0$ Production for Polarized p+p Collisions at $\sqrt s$=200 GeV. Physical Review Letters, American Physical Society, 2004, 93, pp.202002. ⟨10.1103/PhysRevLett.93.202002⟩. ⟨in2p3-00023732⟩

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